1. Field of Invention
The invention relates to labor saving mechanisms and more particularly to a bicycle having a spring-based mechanism operatively connected to an axle of a chain wheel of a bicycle, the mechanism being adapted to store elastic force by counterclockwise pedaling and adapted to release the stored energy by disengaging a clutch from the mechanism when, for example, riding uphill.
2. Description of Related Art
Conventionally, a bicycle is propelled by foot pedals. A rider has to exert a great force to pedal the bicycle when riding uphill, against the wind, or the like. Thus, the rider tends to experience fatigue when riding in such condition.
For reducing fatigue of the bicycle rider, a derailleur is mounted on a bicycle. However, labor saved by the derailleur is limited. It is often that a rider may subject to fatigue when riding uphill even by riding a derailleur equipped bicycle. Thus, the need for improvement still exists.